One year after photo-biomodulation to treat Stargardt disease, best corrected visual acuity (BCVA), microperimetry, and pattern electroretinography (PERG) amplitude significantly improve, according to a study published in Clinical Ophthalmology. This finding may serve as evidence that the therapeutic approach could be useful in maintaining visual acuity and reducing central visual loss progression for these patients.
“Moreover, improvement of PERG N35-P50 amplitude at 3 and 6 months was correlated to BCVA improvement at 1 year, suggesting that PERG could play an important role in predicting visual outcome 1 year after photo-biomodulation,” according to the researchers behind the investigation. “However, a larger sample of patients, a longer follow-up, and quantitative data of the retina are needed in order to confirm our findings.”
They conducted the prospective study at the University of Bologna in 90 eyes of 45 patients (27 women and girls and 18 men and boys, mean age 20 years old) with Stargardt disease stage 1. This disease is the most common hereditary macular degeneration, impacting patients with a median age of 27 years at a prevalence of 1 in 10,000 persons, with no current treatment approved to stop progression. In the study, patients were treated with photo-biomodulation therapy for 1 year for 10 minutes a day, twice a day, and 5 days per week for 12 months using a light emitting diode (LED) of 10 Hz and wavelength 650 nm. Researchers assessed BCVA and microperimetry before treatment and 1 year after, and PERG was assessed at baseline, 1, 3, 6, and 12 months after treatment.
Researchers found that BCVA improved from 0.7 [IQR=0.6–0.9)] to 0.4 (IQR=0.2–0.5)] after treatment (95% CI=-0.3, -0.35, P =<.001) and PERG negative wave at 35 ms (N35)-positive wave at 50 ms (P50) amplitude improved from 0.9 (IQR=0.74–1.21) to 2.12 (95% CI=1.11, 1.28, P <.001). They found that MP-1 microperimetry improved from 26.5% (IQR=16.75– 40) of median preferred retinal loci (PRL) within an area of 2° of diameter to 38% (IQR=29–50.25, 95% CI=10.50, 14.50; P =<.001); on the other hand, PRL within 4° of diameter raised from 72% (IQR=51.5–80) to 80% (IQR=76–87) after photo-biomodulation (95% CI=4.50, 7.50, P <.001).
“Also, patients with an improvement of more than 1.205 PERG N35-P50 ratio amplitude at 3 months and more than 1.29 at 6 months tended to present an improvement of more than 0.2 logMar in BCVA at 12 months (P =.28, AUC=0.630; p=0.30, AUC=0.636),” according to the researchers.
A limitation of the study’s results was how BCVA improvements were not correlated with improvements of PERG and fixation tested with MP-1 at 12 months. More study is needed examining this point, they write. The study’s overall limitations include the low number of patients included; patients were not stratified for different ages and onset of disease; and the treatment was performed frequently (5 days a week for 12 months), so patient compliance could be low in clinical practice. Finally, researchers did not record long-term OCT measurements
Scalinci SZ, Valsecchi N, Pacella E, Trovato Battagliola E. Effects of photo-biomodulation in Stargardt disease. Clin Ophthalmol. 2022;16:85-91. doi:10.2147/OPTH.S344378